E3 spark plugs

[tyst67]

Has anybody used these plugs on a 2 stroke mercury?

[zul8tr]

Has anybody used these plugs on a 2 stroke mercury?

What type, model Merc?

[tyst67]

What type, model Merc?

It's a 40hp mercury sea pro twin 640 cc! Same as the 59ci mercury's 40/50/55/60's except my motor has one less cylinder!

[zul8tr]

It's a 40hp mercury sea pro twin 640 cc! Same as the 59ci mercury's 40/50/55/60's except my motor has one less cylinder!


Do not know what is the standard plug for your engine but according to this manual which I assume similar to your 2 cylinder model?:

http://boatinfo.no/lib/mercury/manuals/40-50-55-60.html#/0

the recommended spark plug is the NGK BP8H-N-10 (NGK part # 4838) which is a 1/2" reach 14mm plug that has a projecting tip design similar to the Champion L gap series (like J6J which are 3/8" reach x 14 mm used in the older Mercs). If your engine uses 1/2" reach x 14mm the NGK is a great plug.

As far as the E3 plugs (I have not tried them) but they just have 3 ground electrodes and that appears to me to be not much of an advantage because the ignition will only fire one electrode at a time depending on which gives the least resistance to the spark based on conditions of the electrode and combustion chamber conditions. The extra electrodes are probably for extra life of the spark plug as the electrodes wear.

The E3 conversion chart

http://www.e3sparkplugs.com/pdf/e3autocross.pdf

does not have a E3 plug for the BP8H-N-10 (#4838) so if you did try them non are listed.

I would go with the standard plug recommended in your manual.

[zul8tr]

It's a 40hp mercury sea pro twin 640 cc! Same as the 59ci mercury's 40/50/55/60's except my motor has one less cylinder!

I have never tried those 3 ground electrode plugs. My guess is that only one electrode will be used based on which at the time has the least resistance for the spark and cylinder temp, etc conditions. I think the extra ground electrodes are for longer lasting plugs and maybe some anti fouling? Look at the surface gap plugs (like L78V) with 360 degree ground electrode, supposed to be less prone to fouling and last longer than single electrode designs. My Merc race engine 25ss came with L78V surface gap and I and other racers dumped them for the L61Y plug that you could read and get better performance from.

Based on the service manual for the 3 cylinder engines you note (59ci mercury's 40/50/55/60) the recommended plug is the NGK BP8H-N-10 (part # 4838) which is projecting center, 1/2" reach x 14mm thread. I assume this is the same plug recommended for your 2 cylinder? It is a great plug (similar in heat range and projecting tip like the L61Y) I tried these NGK's in my 25ss, ran well with no issues at 7100 rpm, finally got hold of L61Y's (NLA- but Bob Wartinger had some) which is still better performing than the NGK for my engine.

As for the E3 there is no conversion for the NGK BP8H-N-10 plug to E3.
I recommend the NGK if that is what your manual states. If not try it but make sure you do not have any piston crown clearance issues.

[fs5]

hi mate ,I've been runnin these br8eix plugs in mine for the past 5/6 hours of use,a mate put me onto them.they gave me a solid 2.5kph more topend.my motors pretty stock ,59 ci 55 merc.i was a bit worried they would be like a big glow plug in there and it would detonate.but so far so good .
its up to you if you want to try them,the theory is they up the compression a tad.
forgot to mention I run an extra plug washer on mine.just check the clearance at TDC from the piston to the top of the chamber.
hers a pic against a standard plug.

[tyst67]

Thanks !!! I just ordered a set :) do the guy that told you about them run the extra washer? Or did you do it just to be safe?

[fs5]

I did it just to be safe ,he ran them on a stock 50 tohatsu.

[tyst67]

I tried the plug but they didn't work right :( they spark knocked really bad for some reason ! I checked to see if they were hitting the piston but there was enough clearance

[fs5]

my motor is stock ,other then reads and a tuner.i only rev mine from 5200/5800 most days.
don't run them if its knocking or you will do some serious engine damage.

[zul8tr]

I tried the plug but they didn't work right :( they spark knocked really bad for some reason ! I checked to see if they were hitting the piston but there was enough clearance

Where do you have the timing set? Is it at factory setting or more advanced? Those plugs protruding like they do into the combustion chamber could cause the engine to need less advance? Measure where it is and kick it retarded some. Is the ignition a CDI or points? I would use the NGK BP8H-N-10 plugs per the OEM recommendation, they are a great plug and similar to the NLA Champion L61Y which is a great plug for high speed running.

[Dan Bunting]

We use E3 Spark Plugs in all 3 of our SST-60 race boats with absolutely no problems. E3 Spark Plug number that we use is E3.32.

[tyst67]

We use E3 Spark Plugs in all 3 of our SST-60 race boats with absolutely no problems. E3 Spark Plug number that we use is E3.32.

Thank you very much! Is there any gains from these plugs?

[Dan Bunting]

We have not done any "official" testing on power gains. We have noticed a slight power gain and feel comfortable using their plugs in our boat. Due to racing, we have not noticed any fuel economy/savings. We have not had an issue with fouling plug, broken plugs, motor not running correctly, etc. The E3 technical staff is very knowledgeable and helpful with any questions or concerns that we have. I would recommend trying them and seeing what you think.

[GTR]

We have not done any "official" testing on power gains. We have noticed a slight power gain and feel comfortable using their plugs in our boat. Due to racing, we have not noticed any fuel economy/savings. We have not had an issue with fouling plug, broken plugs, motor not running correctly, etc. The E3 technical staff is very knowledgeable and helpful with any questions or concerns that we have. I would recommend trying them and seeing what you think.

Where can I get these plugs? How much do they cost per piece?